The present invention relates to an electric thermal ampoule for a sprinkler.
Generally, sprinklers are fire fighting equipment installed on the ceilings of buildings for spraying extinguishing liquid, or water, upon sensing the occurrence of a fire, so as to extinguish the fire.
A typical sprinkler head H comprises, as shown in FIG. 1, an extinguishing liquid discharging nozzle 1 coupled with an extinguishing liquid supply pipe 33 via a pipe coupling socket 23, an O-ring-shaped body 2 extending downwardly out of the outer surface of the discharging nozzle 1, an extinguishing liquid diffusing plate 6 fitted horizontally under and to the lower end of the O-ring-shaped body 2, a valve plate 3 for normally holding the discharging nozzle 1 closed, a trigger 4 installed within a space between the valve plate 3 and the bottom of the body 2 for supporting the valve plate 3, and a thermal fuse 7 installed within the trigger 4. The thermal fuse F includes, as shown in FIG. 2, a hollow drum-shaped casing 11 enclosed at its bottom, low-temperature fusing lead 13 filled within the casing 11 and held solid at room temperature, and an actuating pin 12 held within the lead 13 at its lower end and projected out of the top of the casing 11 at its upper end. As the ambient temperature rises due to the occurrence of a fire, the low-temperature fusing lead 13 in the thermal fuse 7 fuses to become a liquid state, thereby causing the actuating pin 12 to be sunk in the lead 13 and thus the valve plate supporting balance of the trigger 4 to be broken. As a result, the valve plate 3 opens the extinguishing liquid discharging nozzle 1 to spray extinguishing liquid.
There has been proposed another conventional sprinkler wherein a glass ampoule (not shown) filled with a temperature-expansive gas(G) is provided instead of the above low-temperature fusing lead-type thermal fuse as shown in FIG. 3. If a fire occurs, then the gas in the glass ampoule expands to break the glass ampoule, thereby causing a valve plate supporting force to be lost. This sprinkler is substantially the same in operation as that with the low-temperature lead thermal fuse.
On the other hand, the above-mentioned conventional sprinklers using either the low-temperature lead fuse or temperature-expansive glass ampoule have such a structure that the fuse or glass ampoule reacts directly to substantial heat of a fire. In this regard, such conventional sprinklers are disadvantageous in that they have a very slow response to the initial stage of a fire because they are not actuated in the event of the fire until the ambient temperature reaches a fusing point of the low-temperature lead or an expansion-breaking point of the glass ampoule. In connection with such a problem, U.S. Pat. No. 2,245,144, invented by William B. Griffith, et al., shows a technique for breaking or melting the glass ampoule or low-temperature lead fuse using not the fire heat but electric heating means. In this U.S. patent, as shown in FIG. 4, in the event of a fire, a diaphragm (41 in the patent) first expands at a low temperature prior to the melting of the fuse and then applies electric power to an electric heating coil (20 in the patent) around the fuse or glass ampoule. In this technique, the diaphragm functions as a mechanical temperature sensor expanding when the ambient temperature exceeds a predetermined threshold value and also as an electrical switch for applying electric power to electric heating means(electric heating coil) upon the expansion.
Another approach to using the electric heating means around the fuse or glass ampoule is shown in International Application No. PCT/FI93/00164 (International Publication No. WO 93/21998), inverted by Sundholm, Gbran. In this publication, as shown in FIGS. 5a, 5b and 5c, an electric heating coil(8 in the publication) of memory metal is laid around the glass ampoule. The memory metal coil is held contracted at room temperature to hold an electric circuit opened (see FIG. 5a). When the ambient temperature reaches a predetermined threshold value due to the occurrence of a fire, the memory metal coil changes(or expands) its shape to function as a switch for closing the electric circuit. After closing the electric circuit, the memory metal coil functions as the electric heating means for heating the fuse or ampoule. For reference, FIG. 5b shows a state where the memory metal coil expands and makes an electrical connection to act as a heater, and FIG. 5c shows a state where a spindle (5 in the publication) is pressed downwardly (to spray extinguishing liquid) under the influence of a spring (6 in the publication) after the glass ampoule is broken.
The sprinklers shown in the ""144 patent and ""21998 publication comprise the electric heating means for heating the fuse or glass ampoule at a predetermined low temperature before the substantial fire heat reaches the fuse or glass ampoule. In this regard, such sprinklers are advantageous in that they have a faster response to the initial stage of a fire than that of the conventional sprinklers using the glass ampoule or fuse breaking or melting due to the direct heating by the substantial fire heat. However, such sprinklers still have the following disadvantages.
Firstly, because fire-fighting equipment, such as sprinklers, is installed and not used until the occurrence of a fire, it is unused for a lengthy period of time due to the fact that there is no fire. As a result, the fire fighting equipment may be aged or have partially damaged electric circuitry due to a lack of maintenance, finally becoming inoperable in the actual event of a fire. In order to solve this problem, there is a need to frequently test the normal operations of the sprinklers. However, it is not easy to frequently test a large number of sprinklers installed on the ceiling.
Secondly, in almost all cases, a fire starts in a localized area, and only a sprinkler installed in that local area is actuated. Sprinklers installed in other adjacent rooms are not actuated, thereby making it impossible to prevent the fire from spreading to the adjacent rooms. On the other hand, in the previously stated ""144 patent, another switching means (37 in the patent) is provided in addition to the diaphragm-type mechanical/ electrical switching means to manually close the electric circuit. The provision of such other switching means may establish manual electrical connections to sprinklers in other places than the place where a fire stars, as needed. However, this ""144 patent does not show any means (for example, means for connection between sprinklers, means for acquiring information needed for an operator""s operation, command transfer means, etc.) embodied for controlling individual electrical connections to the respective sprinklers.
In consideration of the forgoing problems in conventional sprinklers, the present inventor suggested in Korean patent application No. 2000-8114 (corresponding PCT/KR00/00186) filed on Feb. 21, 2000, as shown in FIGS. 6 to 10, a sprinkler apparatus comprising a heater 14 operable by temperature sensing means, a thermal fuse 13 melting by heat from said heater, and a valve plate 3 for opening an extinguishing liquid discharging nozzle of a sprinkler head in response to the melting of said thermal fuse to discharge extinguishing liquid, wherein said sprinkler apparatus further comprises a sprinkler head controller C including a transmitter and a receiver, said sprinkler head controller performing a self-diagnostic operation according to an algorithm contained therein in such a manner that it supplies a small amount of current to said heater and detects the amount of current flowing through said heater and externally transmitting the self-diagnostic result and a temperature value sensed by said temperature sensing means; and a main computer MC installed in a central control station for informing an operator of said self-diagnostic result and temperature value transmitted from said sprinkler head controller.
The present invention relates to a glass ampoule filled with a temperature-expansive gas for sprinklers instead of the low-temperature melting lead type thermal fuse which is described in the Korean patent application No. 2000-8114.
In the conventional electric heating glass ampoule for sprinklers, as shown in ""21998 publication, an electric thermal coil is provided around the ampoule. In this type of sprinkler, it is necessary to coat the outer surface of the coil so as to prevent corrosion. Furthermore, if it happens to break in the power supply circuit and, thus, no electric power is supplied to the coil, the coil has a harmful effect on the ampoule. This is because it blocks heat transfer and, therefore, the actuating response of the ampoule deteriorates. Moreover, since the size of the ampoule is very small, it is not easy to wind the coil around it. In addition, if the coil is not tightly wound around the ampoule and, thus, there is a gap between the coil and the outer surface of the ampoule, the actuating response of the ampoule deteriorates. Deterioration of the actuating response of the ampoule is also caused from the fact that the direction of heat transfer is from the outside of the ampoule to the inside. Finally, if the coil is manufactured using a thin wire in order to be actuated by low power, it is much more difficult to prevent corrosion.
Therefore, embodiments of the present invention can be made in view of the above problems in glass ampoule type, so as to increase efficiency of heat transfer, actuating response, duration and ease of intallation of the glass ampoule.
In accordance with one aspect of the present invention, an electrically breakable glass ampoule for a sprinkler apparatus comprises a closed hollow cylindrical glass casing, an electrical heating coil installed inside of the glass casing, a negative and a positive electrode are provided on the outer surface of the glass casing, each of the electrodes being electrically connected with both ends of the heating coil respectively and heat expansive gas filling the glass casing.
In accordance with another aspect of the present invention, a thermal ampoule for use in a sprinkler comprises a hollow casing containing a heat expansive gas, the gas having a characteristic rate of expansion given heat, the casing comprising first and second closed end portions located opposite to each other, and a side wall portion formed between the first and second closed end portions; and an electrical coil located in the inside of the casing and conducting an applied current flow therethrough, wherein the electrical coil generates a selected amount of heat in proportion to the current, and the heat is transferred to the gas. The hollow casing is configured to break as a result of the expansion of the gas. The coil includes first and second terminals, the first terminal being configured to receive the applied current, the second terminal being configured to cause the current to flow through the coil. The thermal ampoule further comprises first and second electrodes; and first and second electrical wires connecting the first and second terminals of the coil to the first and second electrodes, respectively; wherein the first electrode is configured to transfer the applied current to the first terminal, and the second electrode is connected to the ground. The first electrode and the connection to the first terminal are located on the outside of the casing, and the first electrical wire passes through the hollow casing in order to connect the first terminal to the first electrode. The side wall portion includes a protruding portion, and the first electrode is located on the protruding portion and shaped in conformance with the shape of the protruding portion. The second electrode is located on the second closed end portion, and the second electrical wire passes through the hollow casing in order to connect the second terminal to the second electrode. The first electrode is located on the first closed end portion, and the second electrode is located on the second closed end portion. The casing is formed from a substantially glass material. The casing has a substantially cylindrical shape.
In accordance with still another aspect of the present invention, a thermal ampoule for use in a sprinkler comprises a closed hollow casing enclosing a heat expansive gas, the gas being selected to expand according to a specific amount of applied heat; and an electrical coil located in the inside of the casing and conducting current therethrough, wherein the electrical coin generates first and second amounts of heat in proportion to first and second applied currents, respectively, and transfers the first and second amounts of heat to the gas. The first amount of heat is selected to allow the gas to expand and break the hollow casing. The second current is smaller than the first current, and the second amount of heat is selected so that the expanded gas does not break the hollow casing.
In accordance with another aspect of the present invention, a sprinkler head for use in a sprinkler comprises a housing defining a liquid supply hole, the hole adapted to supply an extinguishing liquid to the inside of the housing; a thermal ampoule located in the housing and containing a heat expansive gas and an electrical coil therein, the gas being selected to expand according to a selected amount of applied heat, wherein the coil is configured to generate the selected amount of applied heat based on an input current and is configured to transfer the selected amount of applied heat to the gas; a valve plate supported by the ampoule so as to keep the hole closed; wherein the amount of applied heat is selected to allow the expanded gas to break the ampoule, and the valve plate is configured to open the hole in response to the breaking of the ampoule, thereby discharging the extinguishing liquid from the sprinkler head.
In accordance with yet another aspect of the present invention, a method of operating a thermal ampoule for use in a sprinkler is provided. The method comprises applying a current to an electrical coil located in the inside of the thermal ampoule, the ampoule containing an expansion gas surrounding the coil; and feeding the current through the electrical coil so as to generate heat and expand the gas. The amount of generated heat is selected to allow the gas to expand and break the thermal ampoule. The applying comprises providing the current from a first electrode located on the outside of the ampoule to a first terminal of the coil. The feeding comprises feeding the current from the first terminal to a second terminal of the coil, the second terminal being electrically connected to a second electrode located on the outside of the ampoule. The ampoule is formed from a substantially glass material. The ampoule has a substantially cylindrical shape.